Viessmann B0KA - Page 58

58
Displayed fault
code
System characteristics Cause Measures
7 No DHW heating Lead break, cylinder tem-
perature sensor
■
Check DHW setting in the com-
missioning assistant and correct
if necessary.
■
Check the cylinder temperature
sensor (terminal S.T.S).
■
Measure voltage at sensor input
on HBMU heat management
unit. Set value: 3.3 V with sen-
sor disconnected
Replace faulty component if neces-
sary.
8 No DHW heating Short circuit, cylinder tem-
perature sensor
Check the cylinder temperature
sensor (terminal S.T.S).
Replace faulty component if neces-
sary.
13 Regulates as if the outside
temperature were 0 °C.
Lead break, outside tem-
perature sensor
■
Check operating mode setting in
commissioning assistant and
remedy if necessary.
■
Check the outside temperature
sensor and connection to sensor
(terminal O.T.S).
■
Measure voltage at sensor input
on HBMU heat management
unit. Set value: 3.3 V with sen-
sor disconnected
Replace faulty component if neces-
sary.
14 Regulates as if the outside
temperature were 0 °C.
Short circuit, outside tem-
perature sensor
Check the outside temperature
sensor and connection to sensor
(terminal O.T.S). Replace faulty
components if necessary.
49 Burner in a fault state Lead break, flue gas tem-
perature sensor
Check flue gas temperature sen-
sor.
Reset the appliance.
50 Burner in a fault state Short circuit, flue gas tem-
perature sensor
Check flue gas temperature sen-
sor.
Reset the appliance.
57 Normal operation without
room influence
Lead break, room temper-
ature sensor
■
Check commissioning setting of
remote control.
■
Check plug and cable of external
room temperature sensor, heat-
ing circuit.
■
If no external room temperature
sensor installed, replace pro-
gramming unit.
58 Normal operation without
room influence
Short circuit, room tem-
perature sensor
Check plug and cable of external
room temperature sensor, heating
circuit.
If no external room temperature
sensor installed, replace program-
ming unit.
59 Burner locked out, boiler cir-
cuit pump off. No central
heating, no DHW heating
Power supply, undervolt-
age
Check mains voltage.
If voltage is correct and the fault
occurs repeatedly, replace the fan
unit.
Troubleshooting
Fault messages (cont.)
6179762
Diagnosis